package com.example;


import java.io.File;
import java.text.SimpleDateFormat;
import java.util.ArrayDeque;
import java.util.Date;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;

public class SignalDemo {

    public static void main(String[] args) throws InterruptedException {
        ArrayDeque<String> deque = new ArrayDeque<>();
        final String s = deque.peekLast();
        System.out.println("OK");

    }


}
